AcademicIndex.net
"A free metasearch engine and virtual reference desk accessing tens of thousands of academic reference and research sites recommended by teachers and librarians."
Answers.com
"A free, ad-supported, reference search service, created to provide you with instant answers on over a million topics. As opposed to standard search engines that serve up a list of links for you to follow, Answers.com displays quick, snapshot answers with concise, reliable information."
AOL Research & Learn
"Our online reference center is a research database built for you. Use our reference tools, explore space and planet Earth and research college information easily and quickly. If you are looking for information on genealogy research, history or space, turn to Research & Learn."
Bartleby.com Reference
Encyclopedia, dictionary, thesaurus, quotations, English usage, religion and mythology, literature and literary history, anatomy, cooking, etiquette, parlimentary procedure.
Best Information on the Net
From a university library. Includes resources by major, hot paper topics, current events, and more.
Bloomsbury Research Centre
"The Bloomsbury Research centre is a FREE on-line database of reference books. Over 17,000 entries are cross-referenced providing a wealth of information all linked and all fully indexed."
British Library: Collections
Hundreds of thousands of historical materials online, from music to maps the Gutenberg Bible, and more.
ibiblio: Travel the World
Large human-selected directory of links to internet resources on a wide range of topics.
Information Please
Atlases, dictionary, encyclopedia, multiple almanacs, news, weather, and a homework center are among the offerings at this site.
Internet Archive
"The Internet Archive is building a digital library of Internet sites and other cultural artifacts in digital form. Like a paper library, we provide free access to researchers, historians, scholars, and the general public."
Internet Encyclopedia of Philosophy
Definitions range from one screen to several screens long. A work in progress but still somewhat useful.
IPL: Frequently Asked Reference Questions
"Check this handy list of Frequently Asked Reference Questions to see if your question is a popular one... We have compiled brief guides to the resources available both online and offline on these topics."
Library of Congress
The American Memory (archive) Collection, THOMAS guide to legislation, Global Gateway to world culture and resources, and various Special Exhibitions are among the offerings at this site.
Library of Congress Wise Guide
"Designed to introduce you to the many fascinating, educational and useful resources available from the nation's library and one of the most popular Web sites of the federal government. The 'Wise Guide' will be refreshed monthly, much like a magazine, offering links to the best of the Library's online materials."
Martindale's Reference Desk
Tons of reference resources in all sorts of areas from Astronomy to Entertainment to Languages to general Science.
NY Times Learning Network
"The New York Times Learning Network is a free service for students in grades 3-12, their teachers and parents. The site is updated Monday through Friday throughout the year."
New York Times Cybertimes Navigator
When New York Times reporters search for information on the internet, this is the portal they use. Tons of great links, organized by category.
NYPL Digital Gallery
"NYPL Digital Gallery provides access to over 337,000 images digitized from primary sources and printed rarities in the collections of The New York Public Library, including illuminated manuscripts, historical maps, vintage posters, rare prints and photographs, illustrated books, printed ephemera, and more."
ProQuest Discovery Guides
"Discovery Guides brief you in the basics of a subject and offer recent insights, while providing the technological tools to enhance your understanding."
RefDesk.com
Winner of multiple awards as a top reference site, RefDesk contains tons of information in dozens of categories arranged for easy access.
Timelines - Alterna Time
Links to scores of timelines of history and culture, science and technology, arts and literature, popular culture and current events, and science fiction.
University of Wisconsin Digital Collections
"The University of Wisconsin Digital Collections provide quality digital resources from its academic libraries to UW faculty, staff and students, citizens of the state and scholars at large." Tons of great resources!